EPA's Vessel General Permit and Small Vessel General

are low in comparison to catch levels before the mid-1980s.
Critical Habitat
On October 9, 2009, NMFS designated critical habitat for southern green sturgeon (74 FR
52300). The geographical area identified as critical habitat is based upon the overlapping
distribution of the southern and northern species, and encompasses all areas where the presence
of southern green sturgeon have been confirmed or where their presence is likely. Therefore the
geographical area defined as critical habitat is the entire range of the biological species, green
sturgeon, from the Bering Sea, AK, to Ensenada, Mexico. Specific fresh water areas include the
Sacramento River, Feather River, Yuba River and the Sacramento-San Joaquin Delta. Specific
coastal bays and estuaries include estuaries from Elkhorn Slough, California, to Puget Sound,
Washington. Coastal marine areas include waters along the entire biological species’ range
within a depth of 60 fathoms. The principal biological or physical constituent elements essential
for the conservation of southern green sturgeon in fresh water include: food resources; substrate
of sufficient type and size to support viable egg and larval development; water flow, water
quality such that the chemical characteristics support normal behavior, growth and viability;
migratory corridors; water depth; and sediment quality. Primary constituent elements of estuarine
habitat include food resources, water flow, water quality, migratory corridors, water depth and
sediment quality. The specific primary constituent elements of marine habitat include food
resources, water quality and migratory corridors.
Critical habitat of the Southern species of green sturgeon is threatened by several anthropogenic
factors. Four dams and several other structures currently are impassible for green sturgeon to
pass on the Sacramento, Feather and San Joaquin rivers, preventing movement into spawning
habitat. Threats to these riverine habitats also include increasing temperature, insufficient flow
that may impair recruitment, the introduction of striped bass that may eat young sturgeon and
compete for prey, and the presence of heavy metals and contaminants in the river.
Final Protective Regulations
The final 4(d) rule for southern green sturgeon was issued June 2, 2010, and became effective
July 2, 2010 (75 FR 30714). Under this rule, the prohibitions listed under ESA sections
9(a)(1)(A) through 9(a)(1)(G) are applied for the Southern species, including all the ESA section
9(a)(1)(B) and 9(a)(1)(C) prohibitions except for: 1) Certain Federal, State or private-sponsored
research or monitoring activities; 2) Emergency fish rescue and salvage activities; 3) Habitat
restoration activities; 4) Commercial and recreational fisheries activities, if conducted under
approved Fisheries Management and Evaluation Plans; and 5) Certain Tribal fishery
management activities.
Threats
Natural Threats. Green sturgeon eggs and larvae are likely preyed upon by a variety of larger
fish and animals, while sub-adult and adult sturgeon may occasionally be preyed upon by shark
sea lions, or other large body predators (NMFS 2005c).
Anthropogenic Threats. The principle threat to southern green sturgeon comes from a drastic
reduction in available spawning area from impassible barriers (e.g., Oroville, Shasta and
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